This invention belongs to the field of surgical cutting instruments and, in particular, to an electrosurgical active electrode pencil.
In electrosurgery, a high voltage current, for example, one of about 1,500 volts, is introduced through a cable to a hand-held active electrode pencil equipped with a relatively long, thin metal blade which serves to focus the current in the area of the patient being operated upon. Operating in either the "cut" mode to cut through tissue or the "coag" mode to coagulate or cauterize capillaries which have been cut during the surgical procedure, the surgeon places the metal blade of the pencil in contact with the particular tissue site to be affected. Electrical current jumping from the blade to the tissue performs the cutting or coagulating operation as desired. To complete the circuit, the current passes through the affected site along the line of least resistance to an electrically conductive plate, commonly one fabricated of stainless steel, which supports the patient during the surgery.
Electrosurgery has been widely used to carry out surgical operations which are not readily or conveniently performed with mechanical cutting instruments or where bleeding is difficult to control. However, the known type of electrosurgical devices employing the aforementioned electrically conductive plate are subject to a number of disadvantages. Thus, a significant number of patients experience painful burns resulting from arcing currents between the patients' bodies and the underlying plate in areas of poor contact between the two. The known types of devices can interfere with the proper functioning of electronic implants such as pacemakers and have even been known to cause arcing within metallic prosthetic implants such as metal joints resulting in welding of the articulated parts.